1. Field of the Invention
The present invention relates to a burst cutting area (BCA) evaluation device and BCA evaluation method for evaluating the recording quality of a BCA provided on a rewritable DVD.
2. Related Art
In recent years, rewritable DVDs on which the user can write data and can also overwrite have become widely available as recording media. Examples of such rewritable DVDs include a DVD-RAM, a DVD-R, a DVD−RW, and a DVD+RW. A burst cutting area (BCA) of a rewritable DVD is a circular zone near the center of the disc. In the BCA, additional information such as a serial number unique to the disc is recorded in barcode format using a laser.
Conventionally, the quality of the data recorded in the BCA is evaluated as follows. The signal waveform of each RF signal including a BCA signal corresponding to the barcode is displayed using an oscilloscope, and a visual check is made as to whether the absolute value of the signal satisfies predetermined standards. FIG. 1 shows a construction of a measuring instrument used for such a visual check. The drawing also shows a rewritable DVD that is subjected to the evaluation.
In the drawing, a measuring instrument 1 holds a rewritable DVD 101 by means of a shaft 102. A motor 103 rotates this rewritable DVD 101. While doing so, a signal acquiring unit 104 reads an RF signal, and a filter 105 filters the read RF signal. An oscilloscope 106 displays the filtered RF signal.
In one rewritable DVD, the number of bars of a barcode to be checked is around 4000 at the maximum and 2000 on average. Therefore, when a BCA signal corresponding to the barcode is visually observed to check whether all of these bars satisfy the standards, oversights or reading mistakes are inevitable. In other words, the reliability of the evaluation result obtained by such a visual check cannot be fully ensured. Besides, this method requires a great deal of time and manpower.